Pipelines are used to transport fluids in various industries, including chemical, oil and gas, and manufacturing. These industries use processes that require fluid flow rates to be accurately measured. Such measurements are performed at locations known as meter stations using a variety of different meter types. These meters function in different ways. The meters can use differential pressure of the fluid across an obstruction, ultrasonic signal travel times, turbine blade rotational speed, Coriolis forces, or even electrical and magnetic fields being generated due to bulk fluid movement. Almost all of these measurement methods require use of a fluid velocity distribution, known as a velocity flow profile.
To achieve the most accurate measurements, the flow profile of the fluid entering a metering device must be stable, non-rotating, and symmetric. This type of velocity distribution is known as a fully developed flow profile, and it forms naturally in very long lengths of uninterrupted straight pipe. However, having long lengths of straight pipe is impractical and cost prohibitive. As a result, meter station piping often contains elbows, tees, valves and other assemblies that distort the flow profile into an asymmetric, unstable, and distorted configuration. This makes it very difficult to measure the fluid flow rate in a consistently accurate and repeatable manner. Under these conditions, flow conditioners are needed to correct the flow profile of the fluid such that it forms a fully developed flow profile which allows accurate, repeatable measurements to be made.
Several types of flow conditioners exist, including straightening vanes, tube bundles, and perforated plates. These flow conditioners are placed within the pipe upstream of the flow meter. A typical perforated plate flow conditioner consists of a perforated metal plate that is arranged within a pipe orthogonal to the fluid flow (i.e., across the entire cross section of pipe). The perforations or holes in the flow conditioner cause the fluid flow to be redistributed such that it forms a fully developed flow profile. The placement of a flow conditioner upstream of the flow meter ensures that the flow is fully developed before it reaches the meter. This allows the meter to perform significantly more accurate and repeatable fluid flow measurements.
Currently, in order to measure the pressure drop across a flow conditioner, a pipeline in which a flow conditioner is installed is tapped immediately upstream or downstream of the flow conditioner. A separate orifice fitting or orifice flange of the pipeline may be used to house the flow conditioner.